Assessment of the consequences of caregiving in psychosis: a psychometric comparison of the Zarit Burden Interview (ZBI) and the Involvement Evaluation Questionnaire (IEQ).

BACKGROUND: The Zarit Burden Interview (ZBI) was originally developed to assess the level of subjective burden in caregivers of people with dementia. The Involvement Evaluation Questionnaire (IEQ) is amongst the leading scales to assess caregiving consequences in severe mental illness. We aimed to compare the psychometric properties of the ZBI, a generic tool, and of the IEQ, a more specific tool to assess the consequences of caregiving in schizophrenia and related disorders. METHODS: Secondary analyses of a 16-week, randomized controlled trial of a psychoeducational intervention in 223 primary caregivers of patients with schizophrenia or schizoaffective disorder. Psychometric properties (internal consistency, convergent and discriminative validity, and sensitivity to change) were evaluated for both ZBI and IEQ. RESULTS: Internal consistency was good and similar for both scales (ZBI: 0.91, 95% CI: 0.89, 0.94; IEQ: 0.86, 95% CI: 0.83, 0.89). Convergent validity was relevant for similar domains (e.g. ZBI total score vs IEQ-tension r = 0.69, 95% CI: 0.61, 0.75) and at least moderate for the rest of domains (ZBI total score, personal strain and role strain vs IEQ-urging and supervision). Discriminative validity against psychological distress and depressive symptoms was good (Area Under the Curve [AUC]: 0.77, 95% CI: 0.71, 0.83; and 0.69, 95% CI: 0.63, 0.78 - for ZBI against GHQ-28 and CES-D respectively; and AUC: 0.72, 95% CI: 0.65, 0.78; and 0.69, 95% CI: 0.62, 0.77 - for IEQ against GHQ-28 and CES-D respectively). AUCs against the reference criteria did not differ significantly between the two scales. After the intervention, both scales showed a significant decrease at endpoint (p-values < 0.001) with similar standardised effect sizes for change (-0.36, 95% CI: -0.58, -0.15 - for ZBI; -0.39, 95% CI: -0.60, -0.18 - for IEQ). CONCLUSIONS: Both ZBI and IEQ have shown satisfactory psychometric properties to assess caregiver burden in this sample. We provided further evidence on the performance of the ZBI as a general measure of subjective burden. TRIAL REGISTRATION: ( ISRCTN32545295 ).

Interventions for caregivers of patients with dementia.

INTRODUCTION: With the aging of the population, an increasing number of people have dementia, most of whom are receiving home care. Caregivers are exposed to a variety of stressors, which may lead to feeling burdened, or to depression and anxiety. Various programs or structured interventions have been developed to prevent or lessen these negative consequences. The efficacy of these interventions is debated, mainly due to methodological differences between studies. Review studies so far have presented important discrepancies, thus perpetuating a lack of clarity regarding this important geriatric care problem. The effectiveness of interventions designed to prevent or reduce the burden and/or symptoms of anxiety and depression in informal caregivers are reviewed precisely and rigorously. METHODS: A systematic review of randomized controlled studies assessing the efficacy of structured interventions on the variables of burden, depression and anxiety in informal caregivers of patients with dementia. RESULTS: The literature search yielded 997 references, of which 35 met the screening criteria. Of these studies, 51.4% had results that were statistically favorable to intervention. The methodology used varied widely between studies. CONCLUSIONS: Overall, the available evidence favors the implementation of structured intervention programs, although the results are heterogeneous. Psychoeducational interventions yield better results and can be better adapted to the needs of caregivers.

Unidimensional 12-item Zarit Caregiver Burden Interview for the assessment of dementia caregivers' burden obtained by item response theory.

OBJECTIVES: To develop a one-dimensional version of the 22-item Zarit Caregiver Burden Interview (ZBI) by applying item response theory approaches. METHODS: The answers to the 22-item ZBI of 241 caregivers participating in a clinical trial were analyzed 1) with a Mokken nonparametric item response theory analysis to ascertain the dimensional structure underlying the scale and obtain a one-dimensional reduced version, 2) with the Samejima's graded response model to assess the item characteristics of the reduced version, and 3) with confirmatory factor analysis to confirm the unidimensionality of the reduced ZBI version and assess the item loadings to the burden latent variable. RESULTS: Mokken analysis resulted in a major one-dimensional scale comprising 12 items directly related with burden. All items showed scalability indices over 0.30. The scalability for the overall scale was 0.44 defining a medium scale according to Mokken's criteria. An unconstrained Samejima's graded response model showed appropriate fit, and most items of the reduced 12-item ZBI presented pertinent difficulty and discrimination parameters. The results of the 12-item ZBI confirmatory factor analysis fitted to a one-dimensional latent structure for burden (comparative fit index=0.975; root-mean-square error of approximation=0.067; weighted root mean square residual=0.677). All factor lodgings were above 0.40 with items 9 (strained by the relative) and 22 (overall feeling of burden) presenting the highest loadings. CONCLUSIONS: The reduced 12-item ZBI fits a one-dimensional latent variable of burden. Further psychometric studies, focusing on its equivalence for different populations, sensitivity to change, and minimal important difference are warranted.

Efficacy of a psychoeducational intervention in caregivers of people with intellectual disabilities: A randomized controlled trial (EDUCA-IV trial).

BACKGROUND: People with intellectual disabilities (ID) are usually cared for by their own parents, families or informal caregivers. Caring for a person with ID can have a negative impact on caregivers' mental health (burden, depression, anxiety). The main aim of the EDUCA-IV trial was testing the efficacy of a psychoeducational intervention program (PIP) versus standard practice and to see whether the PIP intervention would reduce the caregiver's burden at post-intervention (4 months) and at follow-up (8 months). METHOD: This was a multi-centre randomised controlled trial including 194 caregivers (96 randomised to PIP, 98 to control condition). PIP intervention consists of 12 weekly group sessions. The control group received treatment as usual. Primary outcomes measured included the Zarit Burden Interview (ZBI). Secondary outcomes were caregivers' mental health (GHQ-28), anxiety (STAI) and depression (CES-D). RESULTS: The decrease of ZBI scores was not significant at 4 months. There was significant decrease in the GHQ scores at 4 and 8 months. CES-D showed relevant results at follow-up. Intention to treat analyses showed similar results. CONCLUSIONS: The PIP intervention seems not to be effective reducing burden, but appears to have a positive result on general mental health. The program was well received and valued by caregivers.